1. Field of the Invention
The present invention relates to a cable protection and guide apparatus configured to be connected between a mobile section and a stationary section of industrial machines, vehicles and others to securely protect and guide flexible cables such as electrical cables for transmitting electrical signals or supplying power and hoses for supplying hydraulic pressure and air pressure.
2. Description of Related Art
The prior art cable protection and guide apparatus (also referred to appropriately as the ‘protection and guide apparatus’ or just as the ‘apparatus’ hereinafter) has a large number of link frames each comprising a pair of link plates laterally and separately disposed and connecting plates configured to crosslink the link plates respectively on inner and outer circumferential sides of the link plates when the apparatus is bent (referred to as the ‘cable-bend inner or outer circumferential side’, respectively, hereinafter). The apparatus is constructed by articulately linking the large number of link frames in a cable longitudinal direction so that the link frames can be sequentially bent while keeping a certain radius of the polygonal bend.
Then, as shown in FIGS. 11 through 13 which illustrate the prior art cable protection and guide apparatus 500, shoes 540 are attached on the cable-bend inner circumferential side of the link plates 510 to prevent the cable-bend inner circumferential side of the link plates 510 located below from directly contacting with the cable-bend inner circumferential side of the link plates 510 bent back and located above, thus causing noise and wear, when the protecting and guiding apparatus is used by bending back in the cable longitudinal direction in a long moving stroke as disclosed in Japanese Patent Application Laid-open No. 2007-10087 (Claims, FIG. 1) for example.
As shown in FIGS. 11 through 13, the apparatus 500 disclosed in Japanese Patent Application Laid-open No. 2007-10087 has the shoes 540 each having a rectangular slidable-contact portion 541, i.e., slidable-contact surface 541a, where the shoes 540 on the upper and lower cable-bend inner circumferential sides slidably contact with each other. Therefore, it is inevitable to assure a bend having a large radius R2 and polygonally formed by the slidable-contact portions 541 of the shoes 540 adjacent in the cable longitudinal direction that contact and interfere with each other in moving the shoes by bending back in the cable longitudinal direction between a cable stationary end and a cable mobile end. As a result, there is a problem that it is unable to downsize the protecting and guiding apparatus.
Although it is possible to reduce the radius R2 of the polygonal bend by reducing and downsizing the rectangular slidable-contact surface 541a in the cable longitudinal direction, the slidable-contact surfaces 541a of the shoes 540 facing with each other between the upper and lower cable-bend inner circumferential sides are caught and obstruct with each other. Therefore, there is a problem that it is unable to relatively move the protecting and guiding apparatus bent back in the cable longitudinal direction smoothly between the cable stationary and moving ends and that contact noise is generated.
Still further, because the shoes 540 are engaged only with and supported by the link plates 510, there is a problem that the shoes 540 may fall off the link plates 510 if the shoes 540 are repeatedly slid and moved over a long period of time.
Accordingly, there is a need for a cable protection and guide apparatus downsized by reducing a radius of a polygonal bend formed when link plates are bent back in the cable longitudinal direction between cable stationary and mobile ends and to achieve smooth relative movements of the shoes that face with each other between the upper and lower cable-bend inner circumferential sides by easing impact energy and impact sound of the shoes.